| "If electrons are spheres and so are protons and neutrons, what type of matter is filling up the area in between?" In quantum theory, a particle is described as a probability field that fills space. For example, an electron might have a 2.5% chance of being in some little cube of space, a 10% chance in a nearby cube, and so forth. The rules for how it works are called quantum mechanics. So the particles are fuzzy. They have no defined size, they can overlap with each other, and so forth. As usual, this research has been simplified to the point of silliness for the popular press. What they probably mean is that a particular electron orbital in a particular type of atom was measured to be spherically symmetric. That means that they went looking for lumpiness of that electron's probability cloud and found to be perfectly smooth and round. Particle accelerators have already measured this smoothness at high energies. They crash electrons together at high speed, watch how they scatter off each other, and the scattering statistics are consistent with electrons having no internal bits and pieces. They're just smooth, continuous electron all the way through. (Proton collisions scatter as if there are lots of lumpy bits inside. The bits turn out the be quarks and gluons.) "Can electrons get squished into different shapes depending on arrangement?" Yes. While electrons can overlap because their borders are fuzzy, they repel each other in the process, changing each other's shapes. Even just sitting around in an atom, they often start out various funny shapes because they have wavelike properties: http://en.wikipedia.org/wiki/Atomic_orbital#Orbitals_table |